Relay



7, 1934- o. s. FIELD 1,969,065

RELAY Filed May 15, 1930 2 Sheets-Sheet 1 FIG. 2

$1 ATTORNEY O. S. FIELD Aug. 7, 1934.

RELAY Filed May 15, 1930 2 Sheets-Sheet 2 INVENTO Q M M. ATTORNEY Patented Aug. 7, 34

UNITED STATES PATENT OFFICE Application May 15, 1930, Serial No. 452,666

21 Claims.

The present invention relates in general to direct current relays, and more particularly pertains to a direct current relay employed by railroads at highway crossings for flashing danger 6 signals upon the approach of a train.

Among the objects of the invention, is to pro- -vide a direct current tractive type relay construction having an armature which assumes a central deenergized position, but which assumes each of two extreme energized positions alternately upon the energization of its operating .circuits. Another object is to provide a relay having uniform time characteristics, that is, an equal time period between the operation of the 16 armature from each extreme energized position to the opposite energized position, to thereby cause a uniform and steady flashing of such danger signals as controlled by the contact means of the relay. A still further object is to provide a relay structure which may readily have its time characteristics changed without effecting the uniformity of operation.

Other objects, purposes and characteristic features of the present invention will be in part obvious from the accompanying drawings, and in part pointed out as the description of the invention progresses. I

In describing the invention in detail, reference will be made to the accompanying drawings, in which like reference characters designate corresponding parts throughout the several views, and in which:

Fig. 1 is a front elevation of a relay structure embodying the present invention;

Fig. 2 is a vertical section taken on the line 22 in Fig. 1; I

Fig. 3 is a back view of the controlling contacts of the relay with certain parts shown in section; v

Fig. 4 is a diagrammatic illustration of a relay constructed according to the present;v invention with certain typical circuits shown therewith as applied to an east bound track of a double track railroad at a highway crossing.

With reference to the accompanying drawings, the relay structure shown as a specific embodiment of the present invention comprises in general, a top plate 5 of insulating material, such for example, as bakelite, a magnetic structure, and a contact operating means. The contact operating means is mounted below the top plate 5 being enclosed by a base 6 which is preferably made of glass or other similar insulating material being formed with vertical sides to completely enclose the operating parts, This base 6 is securely fastened to the top plate 5 by means of a bracket 7 withan associated stud bolt 8 and thumb nut 9. There is a suitable gasket 10 preferably of felt intervening between 5 the enclosing base 6 and the top plate 5.

With reference to Figs. 1 and 4 of the accompanying drawings, the magnetic structure of the relay is clearly shown as comprising three core members 11, 12 and 13 which are interconnected at their upper ends by a pair of back straps 17. These core members 11, 12 and 13 are preferably mounted on the top plate 5 in a given plane, with their pole shoes 14, 15 and 16 repectively extending beneath the top plate 5. 7o Mounted on the two outside core members 11 and 13 are their respective energizing windings 21 and 22 which are connected to suitable bind-. ing posts for ready connection into such operat- 4 ing circuits as may be desirable to be used, for example, those shown in Fig. 4.

0n the center core member 12 is a plurality of choke rings 23 preferably of copper, the number of which serves to determine the desired time characteristics of the relay, as hereinso after set forth.

Beneath the pole shoes 14, 15 and 16, an armature 26 is attached to a cradle member 27 having bearings 28 and 29 (see Fig. 2). These bearings 28 and 29 have spindle-like projections 30 and 31 respectively which extend into suitable recesses within a bushing bolt 32. This bushing bolt 32 passes through the pole shoe, 15 substantially on its center line (see Fig. 1) being secured in position by a nut 33. go

The'cradle member 2'? is slotted through the center of the projections supporting the bearings 28 and 29 (see Fig. 3), in such a manner that set screws 34 and 35 may be used to secure the respective bearings in position. .The 'set screw 34 locks the bearing 28 by passing through a suitable recess in 'its side (see Fig. 2). It is noted however, that the set screw 35 does not pass through a. recessin bearing 29 but the locking feature is supplied by a pin 36 which is permanently secured in position. This arrangement allows facility in assembly by first locating the bearing 28 by the set screw 34 with the proper adjustment obtained by locating the bearing 29 which is then permanently secured in position by pin 36; and also, provides facility in repair inasmuch as the set screw 34 may be removed allowing the bearing 28 to be slipped out of place and still determining that the original adjustment may be obtained upon reassembly.

The armature 26 is located beneath each of the pole shoes 14, 15 and 16 with the pivot supporting means as shown at substantially the center line of the core member 12 (see Fig. 1). This allows the armature 26 to be moved toward either the pole shoe 14 or the pole shoe 16, while its position remains relatively the same in respect to the pole shoe 15 by reason of the obtuse angle formed 'by its upper surfaces. On each end of tho armature 26, residual strips 38 and.-

39 are located in a manner to prevent the armature from becoming stuck against the respective pole shoes 14 and 16, it being understood that these residual strips are of non-magnetic metal.

At the front of the relay, two insulated blocks 41 and 42 are securely attached to a portion of the cradle member 27 (see Fig. 2). These blocks serve as mountings for four movable contact springs of which only two are seen in Fig. 1, namely, springs 43 and 44. As seen in Fig. 1, each spring is insulated from the other and connected by suitable flexible leads to its respective binding post supported by the top plate 5. Each movable contact spring is provided with a reenforcement spring shown as reenforcement springs 45 and 46 for movable contact springs 43 and 44 respectively. Also; the movable contact springs are provided with contacting surfaces preferably formed in the shape of a loop, but may be any other suitable type of contact.

In cooperation with each of the movable contact springs are front and back contacts, of

which front contacts 47 and 48, also back con tacts 49 and 50 are supported from the top plate Y 5 in the usual front point and back point relationship to the movable contact springs 43 and 44 respectively. These front and back contacts are shown as adjustably supported by their respective brackets which suitably connect them to their respective binding posts.

The back contacts are so adjusted in respect to the movable contact springs, that both the right and left hand movable contact springs (see Fig. l) are somewhat tensioned when the' relay is deenergized, thus causing the armature 26 to assume a central position, that is, a position that allows substantially'equal spacing between the upper surfaces of the armature and the lower surfaces of the respective pole shoes 14 and 16. This adjustment allows circuits to be completed from the respective binding posts of the movable contact springs to the respective binding posts of the back contacts to serve purposes as hereinafter set forth.

The movement of the armature 26 toward the pole shoe 14 causes the movable contact spring 43, for example, to break with the back contact 49 and make with the front contact 4'7 while the movable contact spring 44 is merely more strongly tensioned against the back contact 50 (see Fig. 1). In a similar manner, the movement of the armature 26 toward the pole shoe 16 causes the movable contact spring 44 to break contact with the back contact 50 and make contact with the front contact 48 while themovable contact spring 43 is merely more strongly tensioned against the back contact 49.

At the back of the relay structure, a rigid movable contact member 54 is suitably secured to the cradle member 27, and is supplied with a suitable flexible lead extending to its respective binding post (see Fig.3). This movable contact member 54 is also supplied with contact surfaces formed in the shape of a loop similar to those shown for the movable contact springs 43 and 44. Associated with the movable contact member 54 are two contact springs 55 and 56 which have limiting brackets or stops 5'7 and 58 against which they are slightly tensioned toward the movable contact member 54. These contact springs 55 and 56, and stops 57 and 58 are so positioned, that the movable contact member 54 makes connection with the contact spring 55 when the relay windings are deenergized and the armature 26 is in its central or mid position, but the movable contact member 54 does not make connection with contact spring 56 when thus positioned.

When the armature 26 moves toward the pole shoe 16, the movable contact member 54 moves from its central position in a counter-clockwise direction, as shown in Fig. 3, breaking its connections with contact spring 55 and making connection with contact spring 56. Then, when the armature 26 moves away from 16 and toward the pole shoe 14, the movable contact member 54 moves from its position in contact with 56, in a clockwise direction, as seen in Fig. 3, to break contact with 56 and make contact with the contact spring 55. The contact springs 55 and 56 are also provided with suitable binding posts.

It is to be understood that the fixed and movable contact members, above mentioned, may be supplied with any suitable contacting material such as silver, platinum, carbon or the like, as may be most suitable for the conditions to be met in practice. It is tobe further understood that,- although the various contacting means have been shown in the drawings as assuming specific forms, they may assume many other forms and still accomplish the proper contacting functions according to the present invention.

With reference to Fig. 4 of the accompanying drawings, a relay R. illustrates in. a diagrammatic manner a relay constructed and arranged according to the present invention, being included within one typical arrangement of circuits as associated with a highway crossing passing over an east bound railway track of a. double track railway system. This stretch of railway track is shown as including an approach track section TS provided with the usual track relay T which receives its energizing current from the usual track battery 60.

At the east end of the track section, a highway crosses the railway track having associated therewith suitable warning signals S and S each shown as including two incandescent lamps. The signal S is provided with lamps 61 and 62, while the signal S is provided with lamps 63 and 64. These incandescent lamps may be supplied with the usual optical arrangements for providing a warning signal of the color light type. The lamps of each signal are intended to flash alternately in accordance with the control supplied by the track relay T and the flashing relay R. The relay R and the sigtrated in the drawing (see Fig. 4) bysuitable arrows.

As the fluxes produced by the windings 21 and 22 flow through the common core member 12, the choke rings 23 have an equal effect on both components. In other words, the inductive characteristics of the winding 21 with its associated magnetic circuit are equally changed in respect to the inductive characteristics of the winding 22 with its associated magnetic circuit by a change in the number of the choke rings 23 on the core member 12.

The use of the choke rings or short circuited windings 23 provides ready means for adjustment of the time characteristics of the armature. This is true inasmuch as the choke rings 23 tend to retard the building up and the decay of flux with substantially an equal effect in both of the magnetic circuits. If for example, the armature 26 is in an energized position against the pole shoe l4, and the associatedwinding 21 is shunted or deenergized, the flux in the magnetic circuit including the core members 11 and 12 is retarded in its decay by the choke rings 23. Similarly, the potential applied to the winding 22 when the winding 21 is shunted causes a flux to be built up in the magnetic circuit including core members 12 and 13, which increase is retarded by the choke rings 23. Thus, the actual response of the armature 26 to the conditions set up for actuating it to an opposite position is retarded in direct proportion to the number of choke rings 23. In other words, the initial actuating condition is the shunting of the winding, but the effective actuating condition is established sometime later when the difference in value of the flux in the two magnetic circuits is sufficient to effectively operate the armature to an opposite energized position.

This delay in the actual attaining of a difference in flux in the two magnetic circuits of a sufficient value to effectively operate the armature, is accentuated in a degree by the magnetic arrangement. This feature may be briefly explained by stating, that the energization of one winding causes the building up of flux in its own pole shoe but does not tend to buck the flux in the opposite pole shoe. Thus, asthe flux in the armature remains of the same polarity, the magnetic circuit formerly energized remains active to hold the armature in its former position until the flux in that circuit dies to a value suiiiciently less than the flux in the magnetic circuit now energized, that the difference in values is effective to operate the armature. This decay of flux in the magnetic circuit formerly energized is retarded by the choke rings in the usual manner.

Also,.the flux in the magnetic circuit now energized is retarded in building up by the same choke rings in the usual manner, inasmuch as the decay in flux in the former magnetic circuit and the building up of flux in the magnetic circuit now energized causescurrent to flow in the same direction in the choke rings. However, as the recay in the flux in the common leg 12 must occur before the flux in that leg may be built up in the opposite direction, the actual delay in response of the armature is substantially equal to the time of decay plus the time of building up.

From the above description, it is apparent that the magnetic arrangement of the relay structure embodying the present invention, inherently permits the delay response of its armature, while the feature of providing a suitable number of choke rings gives a variable adjustment of the time response characteristics to any practical degree which may be desired. This delayed response of the armature determines that it will remain in its energized positions for periods of time in accordance with the characteristics of the structure as adjusted.

The time consumed by the armature in actually operating from one position to the other is a very small percentage of the time consumed in either one of its energized positions. This type of slow acting relay is very adaptable to the usual flashing signals employed at highway crossings, in that it provides means for uniformly flashing the warning signals. In other words, if two warning lamps or signals are to be alternately energized, it is desirable that each may be energized for the same length of time.

Let us assume that an east bound train enters the track section TS. The track relay T is thus caused to be deenergized placing energy upon two incandescent lamps 62 and 63 of the signals S and S respectively, even before the relay R begins operation. Also, should the relay R fail to function for some unavoidable reason, the incandescent lamps 62 and 63 would be energized and a warning signal would be given. One of these energizing circuits is closed from the positive terminal of the battery BT, through back contact 67 of track relay T, wires 68, wand '71, incandescent lamps 62, wire '72, back contact5 0, movable'contact spring 44, wires '73 and '74, to the negative terminal of the battery BT. Simi larly, the lamp 63 receives energy from the positive terminalof the battery BT, through back contact 67'of track relay T, wires 68, '70 and '75, incandescent lamp 63, wire '76, back contact 49, movable contact spring 43, wires '73 and '74, to the negative terminal of the battery BT.

With the track relay T deenergized, energy is placed upon the winding 22 from the positive terminal of the battery BT, through back contact 67 of track relay T, wires 68, 69 and 66, winding 22, wires '77 and '78, winding 21, wires '79, and '74, to the negative terminal of the battery BT.

After a short interval of time the magnetic circuit including cores 12 and 13 will cause the armature 26 to be attracted to an energized position by the pole shoe 16. With the armature 26 in such a position, the movable contact spring 44 is caused to make contact with front contact 48 and thus apply energy to the incandescent lamp 61 of signal S. This energizing'circuit for the incandescent lamp 61 is closed from the positive terminal of the Battery BT, through back contact 67 of track relay T, wires 68, '70 and '71, incandescent lamp 61 of signal S-, wire 81, front contact 48, movable contact spring 44, wires '73 and 74, to the negative terminal of the battery BT. It is noted, that the movable contact spring 43 still makes contact with back contact 49, it being only more strongly tensioned to such position by the movement of armature to this energized position.

With the armature in an energized position against pole shoe 16, the movable contact 54 shunts the winding 22 through contact spring 56, wires 82 and 66, winding 22, wire '77 back to the movable contact 54. As soon a; an effective actuating difference in flux is obtained so that the magnetic circuit including the core members 11 and 12 gains the advantage, the armature '26 is actuated to the opposite energized position against the pole shoe 14. With the armature in an energized position against the pole shoe 14, the movable contact spring 43 breaks contact with back contact 49 and makes contact with front contact 47 thus energizing the incandescent lamp 64. This energizing circuit for the incandescent lamp 64 of signal S--is'c1osed from the positive terminal of the battery BT, through back contact 6''! of track relay T, wires 68, 70 and 15, incandescent lamp 64 of signal S, wire 83, front contact 47, movable contact spring 43, wires 73 and 74, to the negative terminal of the battery BT. Also, the movable contact spring 44 breaks contact with the front contact 48 and makes contact with the back contact 50 energizing the incandescent lamp 62 of signal S through a circuit as heretofore traced.

Also, with the armature 26 in an energized position against the pole shoe 14, the movable contact 54 shunts the winding 21 through contact spring 55, wires 84 and 79, winding 21, wire 78 and back to the movable contact 54. This causes the armature 26 to be energized to an opposite extreme position after an effective actuating difference in flux value is obtained.

This operation of the armature 26 from one extreme energized position to the other is continued so long as the back contact 6'? of trackrelay T is closed. From the above description, it is obvious that so long as this operation of the relay R continues, the incandescent lamps 61 and 63 are energized with the armature in one energized position and the incandescent lamps 62 and 64 energized with the armature in the opposite energized position. Thus, the two lamps of each signal are alternately and uniformly energized causing a warning signal to be given.

When the train passes in an east bound direction beyond the track section TS, the track relay T is again energized causing the warning signal given by the signals S and S to be discontinued.

Although the embodiment of the present invention is shown and described as being arranged to have one particular winding to be the first energized upon its initiation into operation, it is to be understood, that the embodiment may be arranged so as to have both energizing windings actively energized upon the initial energization of the operating circuits.

When such an arrangement is employed the armature 26 moves toward one or the other of the pole shoes 14 or 16 in accordance with the magnetic advantage gained by one or the other of the two magnetic circuits after energization. In other words, the armature isattracted by both of the pole shoes but due to a slight unbalanced condition between the two magnetic circuits, the armature is slightly attracted toward one or the other. This slight movement of the armature causes a greater unbalance which results in the normal actuation of the armature to the corresponding extreme position.

This slightly unbalanced condition which exists upon the initial energization of the relay,

obtains although no attempt is made to create an unbalance when the relay is constructed.

-On the contrary, the two energizing windings have practically the same number of turns; the resistances of these two windings are practically the same; the armature'26 is biased to a mm or central position within practical meas-" urements; and the coremembers and other parts of the magnetic circuits are made as nearly alike as practical. Nevertheless, althoughthe structure is completed as symmetrically as practical conditions permit, the actual magnetic characteristics of the two magnetic circuits are never exactly balanced.

Having described a tractive type flashing relay and its associated circuits as specific embodiments of the present invention, it is desired to be understood that these forms are selected to facilitate in the disclosure of the invention" rather than to limit the number of forms which it may assume; and, it is to be further understood that various modifications, adaptations and alterations may be applied. to the embodiments of the invention shown without in any manner departing from the spirit or scope of the present invention except as limited by the appended claims.

Having described my invention, I now claim:-

1 In a contact operating mechanism, a neutral armature biased .to a mid-position, two electro-magnets, for respectively moving the armature to opposite extreme positions, and, each having a common leg, and means equally adjusting the inductive characteristics of said electro-magnets, said means including said common leg.

2. In a contact operating mechanism, a neutral armature, two U-shaped electro-magnetic actuating means, each having a common leg, and means for equally adjusting the inductive characteristics of said two electro-magnetic actuating means, said means including short circuited windings on said common leg.

3. In a contact operating mechanism, a. neutral armature, one magnetic circuit for actuating said armature, another magnetic circuit for actuating said'armature, said magnetic circuits being in one part common to each other, and energizing means for each of said magnetic circuits connected to cause magnetic fluxes to flow in said magnetic circuits in directions such that the fluxes will flow in opposite directions in said-one common part.

4. In a contact operating mechanism, a neutral armature, one magnetic circuit for actuating said armature, another magnetic circuit for actuating said armature, said magnetic circuits being in one partcommon to each other, energizing means for each of said magnetic circuits connected to cause magnetic fluxes to flow in said magnetic circuits in directions such that the fluxes will flow in opposite directions in said one common part, and means for equally adjusting the inductive characteristics of said magnctic circuits said means including short circuited windings associated with said one common part. I

5. In acontact operating mechanism, a neutral armature biased to a mid-position, two U-shaped electro-magnets for actuating said armature to oppositely disposed positions, each having a common leg, means for alternately energizing said electro-magnets, and means for adjusting the time lag of the response of said armature to said alternate energizations.

6. In a contact operating mechanism, a neutral armature biased to a mid-position, one electro-magnetic means for actuating said armature to one extreme position, another electro-magnetic means for actuating said armature to an opposite extreme position, each of said electromeans energizing both of said electro-magnetic means when said armature is in a mid-position, whereby due to inherent unbalance one or the other of said electro-magnetic means gains a magnetic advantage to. operate said armature to the corresponding one of said extreme positions, and means deenergizing the one of said electro-magnetic means which gains the advantage when said armature is in the corresponding extreme position, whereby said armature is operated alternately to extreme positions.

7. In a contact operating mechanism, a neutral armature biased to a mid-position, one electro-magnet for actuating said armature to one extreme position, another electro-magnet for actuating said armature to the opposite extreme position, said electro-magnets having a common leg, means for energizing said electro-magnets in series, with said armature in a mid-position whereby one of said electro-magnets inherently gains the magnetic advantage, and means for shunting the one of said eiectro-magnets, which gains the advantage, when said armature is in a corresponding extreme position, with said electro-magnets so arranged that the shunting of one of said electro-magnets causes an increase in flux in the other of said electro-magnets, whereby the armature of the relay is operated to the opposite extreme position.

8. In a contact operating mechanism, a pivoted neutral armature two electro-magnets one on each side of the pivotal axis of said armature whereby the armature is swung in one direction or the other according as one or the other of said electro-magnets is energized, said electro-magnets being in one part in common with each other, and means energizing said electro-magnets alternately, said means so effective as to cause magnetic flux to flow in said common part in opposite directions when one or the other of said electro-magnets is energized, whereby upon the energization of one of said electro-magnets immediately following the deenergization of the other of said electro-magnets the response of said armature to said one electro-magnet is retarded.

9. In a contact operating mechanism, aneutral armature pivoted substantially at the center of its axis, three substantially parallel core members, one of said core members located at one end of said armature, another. of said core members located at the other end of said armature, a third core member located substantially over the center of said armature, a pair of back straps connecting said core members at their ends farthest from said armature, and two windings, one on said core member, another on said other core member.

10. In a contact operating mechanism, a top plate, three core members located substantially parallel to each other and in the same plane extending through said top plate, a pair of back straps connecting the protruding ends of said core members, an armature located beneath said top plate and associated with said core members, a cradle bracket for supporting said armature, a plurality of contacts supported and operated by said cradle bracket, said cradle bracket being biased to a mid-position by certain ones of said plurality of contacts, and means energizing said armature to either of two extreme positions alternately.

11. In a relay in combination, a top plate, a casing, a core structure having three spaced legs supported by said top plate, an armature pivoted to the center leg of said core structure and rockable in respect to the end legs. said armature having a plurality of arms projecting therefrom, movable contacts carried by each 01' said arms, and pairs of vertically spaced and horizontally spaced fixed contacts between which said movable contacts are respectively positioned.

12. A relay comprising a core having three legs, an armature pivotally supported to' swing toward one or the other of the outer legs, a winding on each outer leg, energizing means for each of said windings connected to cause magnetic fluxes to flow in opposite directions in the middle leg, and means operating when said armature is swung to either outer leg to place the winding on such leg on short circuit.

13. A relay comprising a pivoted armature, two electro-magnets, one on each side of the pivotal axis of said armature whereby the armature is swung in one direction or the other according as one magnet or the other is energized, means effective when said armature is swung toward either magnet to place the winding of such magnet on short circuit, and energizing means for said electro-magnets to cause the fluxes through the windings of the electromagnets to flow respectively in opposite directions.

'14. In a contact operating mechanism, a neutral armature, two electro-magnets, each having a common leg, and adjusting means for equally adjusting the inductive characteristics of said electro-magnets, said means including said common leg.

15. In a contact operating mechanism, a neutral armature, one magnetic circuit for actuating said armature, another magnetic circuit for actuating said armature, said magnetic circuits being in one part common to each other, energizing means for each of said magnetic circuits connected to cause magnetic fluxes to fiow in said magnetic circuits so that the fluxes will flow in said one common,part, and means for equally adjusting the inductive characteristics of said magnetic circuits, said means including short circuited windings associated with said one common part.

16. In a contact operating mechanism, a neutral armature biased to a mid-position, oppositely disposed contacts operated by said armature, two U-shaped electro-magnets for actuating said armature to oppositely disposed positions, each having a common leg, means controlled by said contacts for alternately energizing said electromagnets, and means for adjusting the time lag of the response of said armature to said alternate energizations.

17. In a contact operating mechanism, a pivoted neutral armature, two electro-magnets one on each side of the pivotal axis of said armature whereby the armature isswung in one direction or the other according as one or the other of said electro-magnets is energized, said electromagnets being in one part in common with each other, and means controlled by said armature for energizing said electro-magnets alternately, said means so effective as to cause magnetic flux to flow in said common part in opposite directions when one or the other of said electromagnets is energized, whereby upon the energization of one of said electro-magnets immediately following the de-energization of the other of said electro-magnets the response of said armature to said one electro-magnet is retarded.

18. In a contact operating mechanism, a neutral armature, two U-shaped electro-magnetic actuating means, each having a common leg, means for alternately energizing said electromagnets, and means for equally adjusting the inductive characteristics of said two electromagnetic actuating means, said means including short circuited windings on said common leg.

19. In a contact operating mechanism, a neutral armature, two U-shaped electro-magnetic actuating means, each having. a common leg, means controlled by said armature for alternately energizing said electro-magnets, and means for equally adjusting the inductive characteristics of said two electro-magnetic actuating means, said means including short circuited windings on said common leg.

20. In contact operating mechanisms, in combination, anarmature, two U-shaped electromagnetic actuating means for the armature, each having a common leg, and a short circuited winding on the common leg for equally adjusting the inductive characteristics of the two actuating means.

21. In contact operating mechanisms, in combination, a movable armature, two U-shaped electro-magnetic actuating means for the armature, each having a common leg, and a means on the common leg for equally adjusting the magnetic characteristics of the two actuating means.

- OSCAR s. FIELD.

DI S O LAI M E R 1,969,065.Oscar 8. Field, Rochester, N. Y. RELAY. Patent dated August 7, 1934.

Disclaimer filed October 10, 1936,

Company.

by the assignee, General Railway Signal Hereby enters this disclaimer to claims 2, 3, 4, 8, 9, 12, 13, 14, 15, 17, 18, .19, 20,

and 21 of said Letters Patent.

[Oflicial Gazette November 3, 1.986.] 

